Re: Signedness of char in BTF

[Yonghong Song <yhs@xxxxxx>]

On 7/22/22 4:25 AM, Jose E. Marchesi wrote:
> > The llvm and pahole generate BTF_INT_BOOL when the dwarf type has
> > attribute DW_ATE_boolean.
> > But BTF_INT_BOOL is actually used in libbpf to differentiate
> > configuration values (CONFIG_* = 'y' vs. CONFIG_* = <value>)
> >
> > In llvm,
> >    uint8_t BTFEncoding;
> >    switch (Encoding) {
> >    case dwarf::DW_ATE_boolean:
> >      BTFEncoding = BTF::INT_BOOL;
> >      break;
> >    case dwarf::DW_ATE_signed:
> >    case dwarf::DW_ATE_signed_char:
> >      BTFEncoding = BTF::INT_SIGNED;
> >      break;
> >    case dwarf::DW_ATE_unsigned:
> >    case dwarf::DW_ATE_unsigned_char:
> >      BTFEncoding = 0;
> >      break;
> >    default:
> >      llvm_unreachable("Unknown BTFTypeInt Encoding");
> >    }
>
> I just sent a patch to make GCC behave the same way:
> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598702.html

Sounds good. Thanks!